alteration
by oikawaa
Summary: lucy knew that everyone had inner demons, but she never knew that her best friend would be a demon, inside and out.
1. reditum

**Summary:** lucy knew that everyone had inner demons, but she never knew that her best friend would be a demon, inside and out.

 **Series:** Fairy Tail

 **Rating:** M

 **Genre:** Tragedy/Romance

 **Pairing:** e.n.d/lucy, natsu/lucy

 **Note:** I don't own Fairy Tail, nor any of the characters.

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 _ **chapter one: reditum**_

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It felt so nolgastic, being with Natsu and Happy again. Lucy had missed them both so much. She couldn't even believe her eyes when she saw them at the Grand Magic Games. And of course, they caused a scene, got arrested, and then got acquitted. Some old Natsu and Happy.

One thing that had baffle d Lucy was the fact that she was unable to sense Natsu's magic.

That was one thing irking at her. Regardless of how ridiculously strong he got, he was still Natsu, the fire dragon slayer and the son of Igneel. How could she not have known that?

But he was with her now, regardless. In flesh and blood. And they were laughing. He was telling her about this monster he beat up when they had first started their trip, just after they had met up with Gildarts, and how he had sent him flying.

Honestly, had he even changed? It would be weird after all that, him still being the same, but Lucy didn't really want that right now. She wanted to be with her best friend, she had missed him so much over the past year.

Well, she was wrong about one thing.

He had learned how to cook pretty well.

"That tasted amazing, Natsu! You need to teach me that recipe." The said boy looked up at her and grinned, patting his bloated stomach. He looked quite happy with himself.

"Do you think I'm a better cook than Mira, now? I could totally put her on the ropes!" He was still grinning. From ear to ear, the infamous Natsu Dragneel grin. She couldn't help but smile herself.

"You can't be serious. Mira-san's cooking is to die for, and I've only tasted one of your dishes. It could be a fluke." She giggled a bit and sighed rather happily, stretching out.

"Pfft, whatever. We'll see!" His grin faltered a little bit, but he didn't say anything. Maybe he was feeling insecure? Maybe he couldn't beat Mira? Well, it was Mira, anyone would be scared facing her—

"Lucy, have you seen Happy?"

"Oh," She looked around. No sign of the blue cat anywhere. She heard Natsu sniff and grumble to himself. "No. I haven't, but he's probably having a bath." He just mumbled to himself some more and tapped his fingers on the table.

Why did it suddenly get awkward? They both had tales to tell. Heck, why could she say anything? He—

Oh.

He did leave her and everyone else. She was a bit uneasy, although she had missed him and was happy he was back, she still felt a bit bitter about the entire thing. Maybe a part deep down inside of her was acting childish and didn't want to talk to him.

He was acting as if nothing had happened. Like he hadn't missed her or anyone. As if he forgot about all his friends and thought he could just come back.

She was about to speak up, but he cut her off.

"That was a dish I learnt when I was younger," He didn't need to finish. She understood. With Igneel, it was a dish Igneel had taught him. That was why he was acting strange.

There was another silence. This time, it felt uncomfortable.

Lucy looked around, her eyes darting everywhere besides him. Although it looked like he was busy drumming his fingers on the table. She followed up the rest of his arm and stopped on his bandage. He had been wearing it ever since she had seen him at the Grand Magic Games.

Well, he had disposed of the bandages he had on his legs and on his left arm, but not the one on his right.

She walked closer to him and gave him a friendly smile, resting her hand close to his own. "Say, Natsu, you've had that bandage on for an awful long time," "Do you want me to change it for you?"

She reached out a bit further, not noticing the alarm that spread out on her friend's features. His eyes went wide, and… flashed? That couldn't have been right—

He whacked her hand away, the clap echoing throughout the room. "Don't touch me!" Her hand stung as he stood up from his chair, knocking it to the ground, along with his free hand slamming on the table. Lucy stared at him in shock, her stinging hand resting close to her chest.

She hadn't noticed it, but she was shaking. She was slightly afraid, Natsu had _never_ done something like that to her before, and he had most definitely never gritted his teeth in anger because of _her_.

"Tch."

Natsu turned away and stormed out of the living room, leaving the blonde behind to wonder what the hell had gotten into him. He had always gotten a bit moody when Igneel was involved, and she would have expected something like this close to his death, but not a year later.

She spoke up, and even though he heard her, he did not look up. "Natsu…?"

She gulped down, an anxious feeling fluttering in the pit of her stomach, and a sudden ache filling up her chest. Her heart was thumping against her chest so hard, she could clearly hear it drumming in her ears.

 _Am I hallucinating?_ She thought to herself, clutching onto her own hands. _For a second there, I swear I saw—_

There weren't anything on or behind his back now that looked again, but she swore she did see something before. It was only for a second, but it had blurred her vision. Even if it was just for a moment.

If anything, it had looked like—

 _Wings._

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omg so i finally finished this chapter. there's at lease three chapters to the story, so expect more. but i would have finished it earlier but i have exams tomorrow (monday for me) so i've been studying. ugh. damn midterms. also, the genre might turn to M eventually.

 **update:** _since my school laptop doesn't allow me on sites like tumblr i couldn't link the artist, bit thanks to_ l1 _who gave me the source, i can now say who the artist and the people who created the theory. the first three chapters are based on a comic from fairytailanddragonscales on tumblr - which you should all check out - but the theory is from little-dragneel and scam15o._


	2. author's note!

i'm sorry, but this isn't an update!

* * *

my laptop's motherboard is screwed, and so i'm stuck with my school laptop since it's not even worth fixing my laptop. my updates will be slow for a while. i have lost pretty much lost all of my documents so i'll have to re-write them from scratch and just copy. really. i'm sorry. i'm writing the next chapter for alteration and a new au at the moment, so expect some stories to be updated and posted soon.


	3. secretum

_**chapter two: secretum**_

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It was in the middle of the night, yet Lucy couldn't sleep at all. She didn't even feel tired. No. How could she after that outburst Natsu had earlier? She not only wanted to find out _why_ he had snapped at her for something so small, but she wanted to know why he wouldn't take those bandages off. It had been eating at her for the rest of the night, especially since Natsu had locked himself inside his room since then, so she decided she would ask him why he was upset in the morning regardless.

She had half expected him to crawl into her bed like he always did, even after when they had fights, he always used to jump through her window and join her in bed. She was kind of hoping he was, because they had only been together for a week or two, she didn't want him mad at her already.

But as for that bandage, she had a bad feeling, so she decided she was going to look when he was asleep. He was a heavy sleeper, he would never know. She would just up wrap then and then wrap them back up. Simple.

Once she felt like there was no chance of him being awake, she slowly sat up and gently pushed Happy to the side of her legs, flinching a bit as he stirred in his sleep. She stayed perfectly still until she was positive he was asleep, and slipped out of her bed. Then, she quietly and slowly tip toed through her house until she had reached the guest room— Natsu's room for the time being.

She peeked through his door, letting out a mental sigh of relief when she was him asleep and snuggling up to that scarf of his. She opened the door a bit for her figure to slip through, the door making a quiet creak before she was now standing in front of the door. Taking a deep breath and a hard gulp, she stepped forward over and over until she had reached his bed.

This was it. She had no idea why she was nervous, but she felt like there was something under those bandages that she shouldn't see. What was under there? She had no idea, but she was determined to find out.

His bandaged arm was in her reach, she felt her fingertips brush against the fabric before his arm moved, his hands now clutching at her wrist that jolted in surprise.

Crap, he really was awake. No use in lying or trying to be stealthy now.

When he grabbed her wrist, he had ended up tugging her towards him just a bit, her knee was resting on his bed while he was sitting up. His eyes seemed to pierce through her a bit, or so it seemed.

"Natsu, about that bandage—"

His hand tugged on her wrist again, and she felt her eyes widen as he body fell limp against his own. Then just as just as he had grabbed her wrist, he pressed his lips against her own roughly.

But just as quickly as it happened, it was over. Lucy's cheeks felt hot, and she was sure she was blushing hard, at least. She looked away in embarrassment and tried to pull away. "Wait, Natsu, this isn't really appropriate— mmpf."

He didn't pull her back to him, but instead lowered himself down and pressed her lips back against her own once again. His hands were now holding her face so she wouldn't pull away again, and her hands were clutching against his forearms. But she wasn't trying to pull or push him away. No, instead, she was kissing him back. She couldn't help it, because deep down she had wanted to kiss him for a very, very long time. It was just a curiosity thing, she used to tell herself.

She closed her eyes and lost herself in the kiss, deciding to crawl onto his lap while he slowly positioned himself so he was just leaning up against his bed. One of his hands moved to her thigh, and she slid her hands up his arms, lightly tracing her nails along his guild mark.

The kiss was passionate and… well, quite hot. Or so Lucy thought. She had no idea Natsu could kiss as well as he was. He hardly seemed inexperienced, which made her feel a bit anxious and embarrassed because she knew that she most likely was.

Not that she was looking for a make out session with him, or anything.

Once she had reached past his shoulder again, she loosened her still clutched hand. Natsu didn't miss the small gleam that came from her hand, then he felt something cool against his skin, but before he could even do anything after his eyes had snapped open in alarm, his bandages were ripped.

He hadn't noticed that she wasn't kissing him anymore, or that her face was at least a foot away from his own. All he could focus on was his bandages falling onto his bed, revealing the dark secret he wanted to keep away from her— his tattoo.

Lucy felt her eyes widen and her heard drop to the bottom of her stomach, and she stared at him with her mouth agape.

"Tha…" She started, her lips trembling. She had noticed he had lifted his arm up more. She could see it perfectly now, his entire forearm covered in black ink that was shaped like flames, while he had a familiar guild symbol on his hand that was not Fairy Tail's. This guild symbol didn't bring warmth and love into her heart, but instead fear and disappear. "That's… a Tartarus… guild mark."

She stared at him, obviously shocked, while he stared at her in annoyance.

Her instincts cut in, and she felt Natsu's eyes change to something dark. Something that she saw when he completely despised an opponent or someone had hurt on of their friends. Hateful, almost. She backed away in fear, just as soon as he slowly got out of his bed and stood up, his eyes burning into her own.

What the hell had happened to him over the past year?

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i don't know why but i found writing this chapter super easy. like, it only took me just over an hour and i think it's rather well written. i can't say the same thing for the next chapter, though. it took me over three hours to do, plus an hour of editing it. and i still feel like it's crap but i'm posting them at the same time to make sure everyone is happy.

remember to review/favorite/follow!


	4. hospes

**_chapter three: hospes_**

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"You're not Natsu at all, are you!?" Lucy and Natsu stared down at each other, a tension between them unlike any other. "Who are you!? What have you done with Natsu!?"

"…Tch." Finally, the said man spoke up, an unusually arrogant smirk appearing on his face. He was no longer glaring or staring at her in annoyance, but was now looking at her in amusement. Really, he didn't want them to get where they did but it was quite an interesting development.

"And here I was thinking I could have had a bit more fun with you," Her eyes widened and she felt herself take a step back slowly, shocked by his words. "But it seems I've underestimated you, Lucy Heartfilia."

This time, she didn't back down. She stared at him with a glare just as sharp as his own.

"Where's Natsu!? I swear on my life if you've hurt hi, I'll—"

He stalked towards her, his grin faltering just a bit before he caged her in his arms against the wall, his face moving close back to her own. For a moment there he considered kissing her again to distract her, but he knew that Lucy wouldn't fall for again. He wasn't even sure she fell for it the first time.

"I hate to break it to you, princess, but I _am_ Natsu."

"Don't lie to me! Natsu would ne—ver…" Her words drifted off as he lightly tapped her forehead with his index finger, her body turning heavy before she collapsed against him, her eyelids fluttering. And then, she was asleep. Her arms dropped to her sides and Natsu heard a clang.

He glanced down curiosity, and spoke up to himself. "That's… a broken key to Aquarius? ...I see… so she used that to cut off my bandages…"

Natsu picked the blonde up in his arms and carried her until he reached his bed, gently placing her unconscious body over the blankets. He smiled to himself as he stood back up properly and rested his hands on his hips.

"Tch… troublesome… I wanted to keep her unaware without altering her memory if possible, but I suppose she was too smart for her own good. You _do_ keep some interesting company, don't you, Natsu? First that shitty blue cat, and now one of the few remaining celestial mages in the world, one who was apparently able summon the celestial spirit king, no less…"

As if on cue, he heard the numb voice in his head. The same annoying voice that had been bugging him for almost a year. The 'real' Natsu, most people would say, but _he_ knew differently. He wasn't real, he was just a pointless soul.

"Still, this _is_ an interesting development. You see, when I kissed her—" He paused, letting the fact that _he_ , and not Natsu, had kissed her. "Her breathing spiked, her heart rate increased, and her hormone levels shot up…"

A vision of Lucy popped into his mind, the same bubbly personality she always had, along with the constant nagging voice. "I only kissed her as a way to distract her, but to think she actually returns your feelings for her…ha!"

He could see him in his mind however this time. He could see his body shaking in anger, he swore he could even _feel_ it. However, he felt anger bubble up in his stomach with what his nagging voice said.

"… _Why?_ " His amused attitude dimmed, and then he growled deep in his throat. "You have the gall to ask me _why_ I'm doing this?"

His body started to shake, and then he felt magic power surge up in his body. He needed to work on his anger, anger awakened his true self, his demon self. "You know very well _why_! Return your body to you? Have you forgotten which one of us came first!? _You're_ the interloper here!"

"I'm Etherious Natsu Dragneel, Zeref's last and most terrifying demon! You're just the temporary identity this hallow shell of a body developed while I was sealed away in limbo by that damned dragon Igneel!" Ever so slowly, his eyes turned from onyx to red, horns bulged out of his skull while wings grew almost painfully on his back, and his some of his skin turned into red scales.

Four hundred years ago he had his life taken from him because of that fire dragon, and he had to watch himself unconsciously only to have his body develop a new personality that he couldn't take over, until now.

"I've had to watch for eons while you took control of _my_ body and lived my life with it, well, I'm taking back what's rightfully mine now, and I'm going to start by destroying everything you've built in this pathetic short life of yours!"

He took a shaky breath as he closed his eyes, trying to calm himself down. Now that he was alone, he didn't have to hide inside the body of a mere human, but instead as E.N.D, the one who came first. Now his 'human' self was stuck in limbo, with no way out.

"Hmm— Natsu…"

He looked down to Lucy who was stirring and sweating in her sleep.

"…And it seems like this silly girl is worth something to you. Well, what should I do with her?" He looked up and thought out loud, making sure his other self could hear him clearly.

"I could erase all memories of you from her mind; I could plant new ones that make you her worst memory. "

He could tell how he was, his body still shaking with anger while he bit his lip to force himself to be quiet. He pondered out loud, "What would hurt you the most, I wonder?"

"Or…" He reached down and stroked her hair, lightly brushing her locks with his fingers. "I could let her keep these _interesting_ memories of tonight and make her my _lover_ instead, what do you think?"

And then it started again, Natsu yelling at him pointlessly. But this time seemed different. It _was_ different. He was louder, and his body was shaking much, much more. But of course, that just made E.N.D happier. He meant what he said earlier, about making Natsu's life miserable while he watched helplessly. And he was going to make sure he did a good job of it.

"Oh, do quit your whining, Natsu. I'm doing you a _favour_. I know you want her. It's irrelevant whether it's me or you doing the deed." He let out a chuckle and crossed his arms, smirking to himself. "After all, you _are_ me."

He stared back down at Lucy, who was still restlessly rolling and squirming around in his bed. He had so many choices to choose from, yet the last one seemed like the best option to pick from, obviously from his current reaction. Natsu was banging against the invisible walls of limbo, and he was even _crying_. How pathetic!

"Don't worry, I promise I won't hurt her… _much_."

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okay so here is the chapter that has made me anxious. i think it's poorly written but i will re-write it in the next two or three weeks just in case. the tumblr artist, who i can't find write now but will link on my profile, only got up to to three parts but hinted at more. if she/he has posted by the time i go to write the fourth chapter i'll write about it. i do have another idea for this story so it will go on for a while longer. maybe around ten to fifteen chapters? but iunno, i'll have to wait and see.

remember to review/favorite/follow!


	5. rubor

_**chapter four:**_ ** _rubor_**

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Lucy's eyes snapped open, slowly blinded by light until she was able to blink into reality. But even then she felt more disoriented. She was staring up at her ceiling, but the room she was in wasn't hers, and she felt like she had barely slept at all. She felt off. She almost— _almost_ — went back to sleep until she realised that she felt more warm than usual. And then as if on cue, she realised with a small squeak of surprise that someone was cuddling up to her like an oversized teddy bear.

Natsu.

She felt his breath hot against her neck as he spoke, and she could literally feel his smirk against ht skin. "Mornin', sleepy head."

Her mouth opened to yell at him (seriously, he was a boy and she was a girl, they couldn't share a bed) but she stopped dead in her tracks. Hazily, she remembered last night. She really wasn't able to sleep, so for some reason she couldn't remember, she had come into Natsu's room. And then… then…

"Luce?"

Her entire face went red as she remembered what else happened, they kissed. And it wasn't just a peck, it was a full on heated kiss, minus the tongues. Had they really done that? Surely, it was just a dream. He wouldn't do that. He didn't like her like that. She forced his arms to loosen around her waist before she sat up, her body still was asleep apparently and caused her to wobble a bit, but she stayed upright.

He puffed his cheeks and let out a grumble before he stared at her, his eyes staring into her with an emotion she couldn't figure out. "Why am I here, Natsu?"

There was a silence before he cocked his head to the side, his lips turning into a toothy grin as he said, "You came here last night, Luce. And you were so heavy I could barely light ya' off the bed! So, I just let you stay here." She frowned at his words. Not because he called her heavy, but because she felt like there was more too it. Like she was missing out on something important.

"I did…?" She asked absentmindedly, before she gestured around the room, opening her mouth again. "Why did I fall asleep here?"

"Really? You can't remember?"

She shook her head and heard him grumble a bit, and then she felt a sharp tug on her arm that forced her back to be pressed against the bed again. She didn't even have time to think about what was happening or to say something, because his mouth had found hers. Hungrily. His sharp teeth had tugged on her lower lip, obviously asking for permission to let his tongue enter. But when he noticed she was just lying there, her eyes wide and her lips not moving against his own, he pulled back.

"Somethin' a bit like that happened. But you were kissing me back then," Oh no, that really wasn't a dream? Her heart started to thump against her chest as she stared at Natsu, who was hovering over her. "We kissed, and then you decided you wanted to stay. So I let ya'."

"But why…?"

"Because," He started, his face drawing closer to hers. But he stopped shy of her lips and let his hot breath make her lips twitch. "After we kissed, you lamely stuttered out that you loved me—" She had used the love word already? How embarrassing. "And you went even redder when I said that I loved you too. And when I said I wanted to be with you, you just fell asleep all of a sudden. You left me hangin', Lucy."

Apparently, he wasn't finished, because he began to pamper soft kisses on the corner of her lips. "Fuck. You have no idea how much it sucked to leave you behind, I missed you so much. I looked up at the stars and tried to remember the ones you told me. I watched the sky every God damn night and you're still the brightest star I've ever seen."

Lucy's eye began to water. She had watched the stars every night as well, in hopes that the brightest star would lead him home. Back to his friends. Back to _her_. She reached up and cupped his face in her hands, and Natsu took it as an invitation to lean forward.

And they kissed, and how so tender and sweet the kiss tasted. His lips were hot and rough, but they felt wonderful on her own, and she fully welcomed them. It wasn't until he pulled back did she realise how much she wanted the kiss to keep going. She tugged him closer again, and he wasted no time in pushing his lips to hers. But this time it was rougher. He wasted no time in forcefully tugging on her lip and pushing his tongue into her mouth. His tongue fought with hers even though in all honesty, she wasn't the dominant type and didn't hesitate to suck on his tongue, just to make sure his tongue didn't leave her mouth.

She had no idea how long they had kissed for, but the dragon slayer had pulled back with huffs and pants. Air. That's right, she needed it, didn't she?

Her chest heaved up and down, while her tongue studied her own swollen lips. He seemed to be in better condition, his face pulled into a— forced grin. Yes, she knew that face. He was faking a grin. Why? Had she done something wrong? That was the face he got when someone mentioned how long it had been since Natsu had seen Igneel. It was one he did when he didn't want his friends to worry.

"Go out with me," He breathed, his voice surprisingly husky.

But despite herself, she shook her head. The odd feeling in her gut had never left, and she was suddenly feeling anxious, this was all moving too fast and nothing seemed to be making sense— she couldn't even speak. A part of her was screaming at her to wake up, but she was already a wake. It wasn't until she felt pain in wrist did she snap out of her thoughts.

"I said, go out with me." This time he sounded more forced and he no longer wore the fake grin. His teeth were gritted and he was glaring down at her, an unamused look in his eyes.

"Natsu?" She asked, but he just shook his head and applied more pressure on her wrist, his hold only tightening the more she struggled and asked him to stop.

What was she doing anyways? She didn't remember any of that. She didn't remember confessing or falling asleep in his arms, and she really didn't think that's how she would be. She was wide awake when she had come into his room.

He let out a sigh and crawled on top of her, one hand staying on her wrist before he lightly touched her forehead, her vision blurring before she felt a sudden, intense pain go through her brain.

And then it was blank.

She couldn't remember what she was doing, all she knew is that at the moment, she would do anything Natsu asked. And that her eyelids were getting heavy.

Letting his earlier act drop, the demon let his now red eyes burn into her own, urging her to say the right answer. "Will you be my lover?" She just nodded, words unable to form. She was confused. She felt blank and dizzy. She could barely remember anything. She couldn't even move.

The hold on her wrist let go all together and the man got off of her, lifting his body off the bed. He stretched and looked over his shoulder, giving the blonde a sadistic smile before he moved towards the door.

"Sleep well, Lucy Heartfilia. You'll be a great toy for _him_."

And then, she saw nothing.

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oh my gosh, i've been editing this for days and i'm still not happy with it. oh well. i still have a plot to this story and i'm going to stick with it. even if i can see myself editing each chapter over and over again. anyways! i'm on holidays at the moment, so i'm working on the next chapter for a love like war. but i pretty much only have one week left until school again but i'll keep trying. i'm also working on a nalu week drabble.

review/favorite/follow!


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